Visual Studio can't read submodule definitions in Bpy
The problem was that for some reason the available docs don't work for Visual Studio Community, but they do work for VS Code. 

I feel like VS Community just doesn't know where to look for the rest of the definitions bc if you move the entire 2.83 file from bin\Release\ to C:\Python37\, the IDE actually shows some code suggestions but not everything. At this point it's easier to just use VS Code for addon development and VS Community for blender development